1. Field of the Invention
The present invention relates to an improvement in a cleaning unit for flow lines such as ducts, conduits or the like through which fluid foodstuffs, chemicals and the like are conveyed to the desired location, and in particular a cleaning unit to remove the deposits from the inner surface of the flow line, which are residual in the flow lines after the completion of conveyance of any fluid material.
2. Description of the Prior Art
In conveyance of slurry material such as ice cream, mayonnaise or powdery material through the flow lines, it is inevitably required to remove deposits from the inner surface of the flow line, which are residual in the flow lines after the completion of conveyance of any fluid material, thereby to keep the flow lines clean against the contamination with another fluid flow to be transported subsequently. To cope with this, cleaning tools have been well known, which are pumped through the flow line to remove or scrape the residual deposits from the inner surface of the flow line or tubing.
Disclosed in U.S. Pat. No. 3,667,544 is a prior duct-cleaner in which an elongated scraper body comprises first and second scraper members and a slender connector member operatively connected to both the scraper members and the elongated scraper body is forced to move in the tubing with making contact with the inner surface of the tubing so as to remove or scrape the deposits from the inner surface of the tubing. Another prior conduit-cleaning device is shown in U.S. Pat. No. 1,218,005 in which a length of flexible wire has around the periphery thereof a plurality of radially-extending brush units and is provided at the lengthwise opposing ends thereof with suitable guiding and propelling elements. Movement of the cleaning device in the conduit causes the brush units to scrape the residual material from the inner surface of the tubing. Any prior art is not only complicated in structure but also short of fluid-tightness or close contact at the interface between the scraper elements and the inner surface of the tubing. In particular, the severe problem has arisen such that it is very hard to remove the deposits at the relatively short radius bents with reliability and efficiency. To overcome the problems as described just above in the prior art, the present inventor developed the cleaner unit of the type disclosed in detail in Published Examined Utility Model Application in Japan No. (Hei)6-18629, in which a slender connector member integral at its lengthwise opposing ends with spherical guiding bodies is provided around the periphery thereof with doughnut-shaped annular pressure-carrying surfaces. The pressure of the material forced in the tubing may apply on any associated one of the annular pressure-carrying surfaces so as to urge the outer peripheral edge of the doughnut-shaped surface against the inner surface of the tubing thereby enhancing the fluid-tightness between the interface between the cleaning unit and the inner surface of the tubing, resulting in reliable scraping of the residual deposits in the ducts, pipes, tubing and the like. This type of the cleaning unit is used extensively for the flow lines conveying wide variations of the material.
Nevertheless, in the cleaning unit according to my prior invention as described above, the unit is entirely made of elastic material such as rubber and also the annular pressure-carrying surfaces are arranged in close relation with the slender connector member. This design requires rendering the cleaning unit greater in whole length or large-sized in order to keep the scraping edges of the unit at the attitude normal to the inner surface of the tubing at the bents in the flow lines. This makes larger the resistance exerted to the cleaning unit pumped through the flow line, especially, meandrous flow line having the successive bents, resulting in making greater the pumping pressure to propel the cleaning unit. This trend becomes a major problem in which the cleaning unit may gain high speed just after negotiating the bents so that the violent vibration may occur at every movement of the cleaning unit through the bent, resulting in causing the vibratory shock that may apply against the coupling joints and supporting sections of the flow lines whereby the tubing becomes deteriorated in mechanical strength. Moreover, the high pumping pressure may causes the disadvantageous deformation at the elastic connector member to thereby deteriorate the fluid-tightness of the cleaning unit with the inner surface of the tubing.